Safety is of paramount concern in the aviation industry, and an ability to warn the pilot of potential impending issues is desired. A sensor system capable of measuring torque output, vibration, thrust, bending loads and engine speed of an engine over time is one potential indicator of engine and propeller health that is not currently being monitored due to the challenges of measuring these parameters long-term.
In addition, data such as engine output torque and thrust can be used to optimize the aircraft setup, either for improved performance or for improved fuel economy. Such optimization strategies are currently limited, as torque data is typically only collected during testing and certification stages of an aircraft. Long-term engine torque measurements have hitherto not been available at all, or have not been available due to the high cost of obtaining such information.
In addition, some aviation authorities, such as the Federal Aviation Administration (FAA) in the United States, require that aircraft engine output torque be measured dynamically over a range of speeds, with the engine and propeller attached to the airframe. For these three reasons, health monitoring, performance optimization and regulatory requirements, it is desirable to measure such data in the real-world, and record the data throughout the life of the aircraft.
Furthermore, it is sometimes desirable for a pilot to view this data both in flight and during pre-flight engine run-ups, and to use the information in conjunction with other engine data to establish warning parameters, with displays and alerts shown in the cockpit. Such data could also enable the pilot to avoid undesirable operating conditions, such as resonant frequencies of the propeller drive system. Since the propeller is rotating with respect to the aircraft cockpit, a wired device cannot be used for this application.
One example of a current system includes U.S. Pat. No. 8,991,267 B1, which discloses a wireless engine torque measuring system and housing mounted to a hub located between the engine and the propeller. The disclosed system contains a wireless measuring device that transmits a strain gauge signal to a receiver using a cable-less communications system, and details the housing used to protect the measuring device. The system is designed to meet the regulatory requirements of measuring engine output torque, but does not measure other operating characteristics such as bending loads and thrust. It also does not address power requirements of the system, which is desired of long-term measurements, and does not address the collection of high speed data, which is necessary to determine individual engine cylinder performance. In addition, it does not disclose real-time display of the data, or methods to use the data except to report engine torque. The system also requires the use of a bulky housing to protect the measuring device, adding cost and weight to the aircraft. The system is also limited to measuring torque and temperature. Furthermore, the system relies on mono-directional communications from the remote unit to the base unit, precluding the ability to alter data collection parameters, such as data rate.
Another example of a current system is U.S. Pat. No. 8,813,581 B2, which discloses a force measuring device mounted to a hub located between the engine and propeller. In this device, coils are required to power the measuring device and to transmit the data to a base unit. These coils limit the system to use in a wind tunnel. However, this device also does not disclose real-time display of the data, long-term data collection, or methods to use the data for health monitoring purposes.
Due to the limitations of the prior art, there is a need for an engine output measuring and monitoring system capable of operating throughout the life of an aircraft, and capable of displaying high-speed, real-time data to the pilot for pre-flight and in-flight use. There is also a need for a configurable warning system, should measurement data fall outside the limits of a pre-configured range. There is also a need for a transceiver based system that uses bi-directional communications for the purposes of updating data collection parameters. Furthermore, there is a need for a system that can be left in the aircraft for long-term health monitoring.